Control device



A. E. BLOMGREN 2,698,657

CONTROL DEVICE Filed Jan. 22, 1954 7a 74 'JNVENTOR.

AXEL E. BLOMGREN ATTORNEYS United States Pate'nfOfiice 2,698,657*Patented Jan. 4, 1955 CONTROLv DEX ICE mond Engineering Laboratory,Inc, Middletown, Conn acorporation of Connecticut Application January22, 1954, Serial No. 405,576

' 4".Claims.. 'l(Cl'.'.161- --1) The present inventionrelatesioaccelerationresponsive delayed action control devices.

An object of thenpresent invention is to provide a devicesfor initiating.a mechanical movement .when subjected to a ,changein velocity. inexcess. of apredetermined degreeand for a duration in..excessof apredetermined amount.

Another object. is..to. provide adevice .of.,.the'above characterwhichis .simple, rugged, .compact,;inexpensive and dependable.

' .Otherfobjects. .will be in;partj.obvious, and in .part pointed outmore in detail hereinafter.

..The.. invention...accordingly...consists .in..the features ofconstruction, combination of .elementsand arrange.- mentjof partsrwhich.will be-exernplified in the constructionhereafter. set forthand the:scopeof the application of which will be. indicated in the appendedclaims.

.,.In the. drawings:

1 'Fig. 1 is aiplaniviewjof.a.device. constructed-in accordance withthe. presentinvention with certain portions cut away to showthe.arrangement ofparts;

I Fig. 2. is another .view of the rstructureshown inFig. 1 showing the.arrangement. of parts, in a .preset. condition forv operation responsive.to. acceleration;

Fig. 3; is a front view of,the structureshown in Fig. l; .ilFig. 4. is afront viewofthe structure shown. in ,Fig. 2 illustrating, themovementgof certain parts thereof; in resplonseto .acceleratiomand Fig..5 is anHenIarged sectional-.viewofthe structure of .Fig. 4.takenon.the1ine-5.-5.-thereof.

. Referring to thedrawingwherein like reference ch aracters...denote.likeapartsninthe :several views, a device of the type witlrswhich-thepresentinvention is particularlysuitable :incl-udesgenerally a controlmember 2 whichis arranged-to .bedriven at a controlled rate by a clock.mechanism 4. or the .like, 'the clock .mechanism being prevented fromrunning by the --mechanical interferenceof a slid-ing.,weight,6.kThe-weight 6 is-rnounted for sliding-movement out.ofinterfering-relation.with clock-.mechanisrrr 4 whenrthe deviceis .-sub, ect,to acceleratiom.and... thereafter? thea .running of .clock -mechanism 4.drives..controlmember 2,to therproper position necessary to initiate .whatever control:action,-suchas-the trippingof a levenoraclosingzof a-switch is desired.

. .The:.devicesincl-udes, a-. generally- U-shaped-wframe Shaving-upstanding sides -.-10,-.; llwand' a -.flatbottom' 12. Secured-tobottom 12 is a bushing'H-inwhich is rotatably mounted a shaft1-16 on:whichis supported an actuating =lever..18- which-emay be employed -toaccomplish .any desired:v operation suchwasmlosing a-. switch, moving alinkagenetc. :The'lever 18 is biasedfor rotation in acounterclockwise:direetionas viewed: in Figs. 1 and .2 by a coil springw20 wound:around rancenlarged hub, of (shaft-16 and secured at.Onerendto lever- 18 and at the. other end to .awping22tdepending fromthe bottom 1220f frame 8.:.-Pin:22 alsogservesxas alstoprfor limitingcounterclockwise movementof thelatch.

- TherleVerEIS-iscadapted to:.be::held inywhat may be termed a cockedposit-ion -asshown in Fig. 2 of the drawing, close to its extremeclockwise position, .by a control member. 2,:inthe'forrn of a" rotatablelatc Control member 22has a flat 24 on-its periphery, however, so thatwhen; rotated. to the proper position'with the fiat 24 alignedwithlever.'13,..levenr18 is released from its cocked pc-sition:and spring:Qthcarries it :counterclockwiseto the positionwshown in-Figs. 1;thecresulting movement of leveiv.:18:ser-ving r to.;perform:ia-nvdesired; pperation.

' The control .member, 2 is fixed to. one end of a shaft 26, which isthemain drivingshaftofthe spring-driven clock mechanism 4. and ismounted. for rotation in a pair of parallel plates 32, 34 .spacedapartby. posts 36and secured to the bottomof frame 8. I Secured to the bottomAxel. ErBlomgremiKensingmn, eolmgassignorto, Ray t plate 32 is a springcover 40..w1th1n WhlCh. is housed the main spring 42 of clockmechanism4. One .end ofmain spring 42 is secured to. spring cover 140 ina,.conventional manner and the other: end is. secured ,to aflange=44onshaft 26. .so as. tmbias. shaftt26 for rotation .in. a counterclockwisedirection as viewed in .Figs. land 2.

Onthe opposite end of.shaft.26 fromthe. control member 2 is mounted themain driving gear 46.0f the clock mechanism. Driving. gear46 is.connected through pinion 48 andintermediate. .gear train- 50 to a.conventional v; reversible escapement .52, whichserves to control ,the

rate at whichdriving gear .46 is. rotated when theclock mechanism 4 isallowed.-to run.

Between thesides 10.. and .11 ,of. frame 8 issupported a pair of slides56, 58. and a guide 60, whichqform a track for the sliding weight 6v and:confine..its., path of movement to a plane substantially normal to,.theclock main driving shaft 26. The weight 6 is bored outto slidablyreceiveguide'60. A compression spring 62 is supported on guide.60,,.and.acts between side ,10,of the frame and the bottom of a counterbore 64inweight 6 to bias the weight-to itsrestposition, asshown in Figs. 1 and2, at which it bears againstthe side ,11 of frame,8.

The shaft 26. is hollow, and supported withinthe shaft is a stifftorsion wire 70 which is bent over at its. lower end.72, as shown inFig. 5, and confined in a transverse slot 74 provided in thelower endofthe shaft26. The torsion wire 70 is thus fixed for rotation with shaft26 at its extreme lower end, and is supported.againstsubstantial bendingor flexing bv the hollow shaft. 26,.but is free to twist Within shaft 26at its upper end responsive, to

fit)

torsional forces imposed upon it.

At the upper end of .shaft'26.the wire .70 is provided with a cam.76 inthe formof an integral extension of the wire itself, bent over as itemerges from shaft '26 into a plane parallel toithe bottom of frame 8.and extendingoutwardly from,the axis of shaft 26 with agenerallv-involute-shaped curvature. The upper end of wire isprestressedin a clockwisedirection as viewed in Figs. 1 and 2 so as to have atendencv to rotate counterclockwise relative to .its lower end. The wire.70 is maintained in its prestressed condition by a stop 78. on the maindri ing gear.46 against .which the cam portion 76 bears. The arrangementis such that a torque ap lied to the top of the wire 70 tendin to rot ethe wire in a clockwisedirection as shown. in Fig. 1' will betransmitted torsio lly through the-length of the .wire and rotate shaft26 clockwise. which is the reverse of the directi n of r t tion of theshaft 26 bv the clock main sorinq 42. Depending from he tom side f theWei ht 6 is a pro ectinn or pin 80 which is of sufiicientlentzthtoextend below the l ne f-the cam 76 formed bv,the bentover p rt n ofwire 70. Pin 80. is s aced cl se enou h to shaft .26-toenaace thecam 76when wei ht 6 is in its rest position and the clockspring 42 is .wound,and thus prevents the clock mechanism 4.from running until weight 6 isdisplaced away from its restposition by acceleration. When weight 6.is;disolaced by.acce1eration, pin 80 disengages from and releasescam-76,.and

- the main drivingugear 46 and shaft 26 willrbe rotated counterclockwiseby clock, main spring .42, the rate .of rotation" being governed by theescapement'52.

The operation of the device will.now be described. Assuming that thedevice is conditioned for-operation, asshown in Fig. 2 the lever 18is-in cocked position and retained in its cocked position by the arcuateportion-of the control member 2; the clock main spring being woundup andbiasing the-torsion wire 70;and cam 76 in a counterclockwise. directionas. shown in' Fig. 2. However, the wire 70;,is retained in its extremeclock wiseposition asshown in Fig. 2'by engagement with. the pin :80 ofweight 6, the-weight 6 and its pin ,8!) being held inobstructingrpositionby: the:spring, 62.

. 'When, the device is...the.r.eafter subjected, to acceleration in thedirection of guide 60, sufficient:toiovercomegthe force of spring 62 onweight 6, the weight will be displaced along the slides 56, 58 towardside 10, as shown in Fig. 4. As weight 6 is displaced toward side 10,pin 80 is disengaged from cam 76 which permits the cam to rotatecounterclockwise and thus permits the clock mechanism 4 to startrunning. If weight 6 returns to its rest position before the bent-overportion of the wire forming the cam 76 has rotated beyond the path ofmovement of the pin 80, it will be appreciated that pin 80 willre-engage cam 76 and will return the cam to its extreme clockwiseposition as shown in Fig. 2, thereby rewinding the clock mechanism andreturning the device to original condition. However, if the accelerationforce is of sutlicient magnitude to displace weight 6 far enough so thatpin 80 clears the end of the bent-over cam portion 76 of wire 70, andthis displacement is of sufiicient duration so that the end of cam 76passes the line of movement of pin 80, subsequent cessation ofacceleration and return of the weight to its rest position will beunable to stop the rotation of the main driving gear 46 of the clock.The clock mechanism thereupon drives cam 76 progressivelycounterclockwise toward its extreme counterclockwise position, as shownin Fig. 1. As the main driving shaft 26 of the clock rotates, of course,the control member 2 is rotated with it in a counterclockwise direction,as shown in Figs. 1 and 2. When the control member 2 has rotated farenough, as shown in Fig. 1, to bring its flat side 24 into alignmentwith lever 18, the control member can no longer retain the lever and itfalls under the influence of spring to its extreme counterclockwise oractuating position, thereby performing whatever actuating operation isdesired.

Thus, it will be appreciated that if the acceleration force on theweight is sufficient in duration and degree to carry pin 80 past the endof cam 76 and hold it there long enou h to allow clock mechanism 4 torotate cam 76 past the line of movement of the pin, the release of lever18 from its cocked position to its actuating position will inevitablyfollow after a predetermined time interval.

The de ree of acceleration reouired to insure release of cam 76 isdetermined by the len th and shape of the bent portion of the wire 70,and this len th and shape also determines how long the wire must berotated before its end clears the path of movement of pin 80. Thus by aprover choice of length and shape for this portion of the wire. anydesired minimum values for the degree and duration of accelerationrequired to release the clock mecha ism may be chosen, and delay of therelease of lever 18 by control member 2 for at least the requiredacceleration duration will be insured.

An important feature of the invention is the use of a cam 76 in the formof an elongated wire 70 anchored at one end for torsional movement whichpermits the use of a relatively heavy weight 6 and spring 62 with aclockworks mechani m of li ht construction. As will be appreciated, asudden cessation of acceleration which has caused displacement of weight6 a ainst spring 62 will cause a sudden return of the weight to originalposition, particularly if spring 62 is of relatively heavy construction.The resulting momentum of the weight, particularly if the weight isrelatively heavv, will create a heavy impact against cam 76, which wouldtend to cause breakage of the mechanism and particularly the clockworks4. By desi ning the wire cam so that it will have suflicient torsionalstren th to withstand material twisting when subiected to the force ofthe clock mechanism 4 but suflicientlv weak that it will twist whensubjected to the heavv impact of the moving wei ht 6, it is insured thatthe device will operate accurately, and at the same time will not breakunder varying conditions of operation. The prestressing of the wire 70and its engagement with pin 78 lends greater accuracy to the device andalso permits the use of a wire of smaller gauge. Also, the mounting ofthe wire within the hollow shaft 26 of the clock mechanism 4 insuresadequate support of the wire against bending or flexing, and at the sametime renders the device exceedingly compact, since the portion of Wire70 subjected to torsion is at least as long as the hollow shaft andrequires no additional space other than that taken by the clockworkmechanism itself. Moreover the construction of the cam in this manner issimple, and it is convenient and easy to fabricate and assemble.

As many changes could be made in the above construction and manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language in the following claims isintended to cover all of the generic and specific features of theinvention herein described and all statements of the scope of theinvention which, as a matter of language, might be said to falltherebetween.

.1 claim:

1. In an acceleration responsive delayed action control device having arotatable control member driven at a control speed, a weight supportedfor sliding movement away from a rest position responsive toacceleration, and a spring biasing said weight toward said restposition, means for governing operation of said control membercomprising a projection on said weight adapted to move in a linear pathresponsive to sliding of said weight, a cam carried by said controlmember adapted to be engaged by said projection to prevent rotation ofsaid control member, said cam comprising a wire having a convexly bentportion lying in a plane parallel to the path of said projection and ashank portion perpendicular to the plane of said bent portion, and atorsional con- Eection between said shank portion and said control mem-2. In a device for delaying the operation of an actuating member until apredetermined time after the imposition of an acceleration ofpredetermined duration and degree, said device having a clock mechanismwith a rotatable driving shaft, a control member driven by said clock, aweight supported for sliding movement away from a rest positionresponsive to acceleration, and a spring biasing said weight toward saidrest position, means for controlling the operation of said clockcomprising a surface on said weight adapted to move in a linear pathresponsive to sliding of said weight, a cam on said clock mechanismadapted to be engaged by said surface to prevent running of said clockmechanism, said cam comprising a wire having a convexly bent portionlying in a plane parallel to said linear path and a shank portionperpendicular to the plane of said bent portion, said bent portiondefining a camming surface having a lift corresponding to the degree ofacceleration and extending over an included angle corresponding to theduration of acceleration, and a torsional connection between said shankportion and said driving shaft.

3. In an acceleration responsive delayed action control device of thetype having a rotatable control member driven at a controlled rate, anacceleration responsive sliding weight for releasing said control memberand a spring biasing said weight to a rest position, a cam resilientlysupported on said control member and rotatable therewith, a projectionon said weight engaging said cam in the rest position of said weight toretain said control member in the unreleased position, said cam beingcurved so as to intercept the line of movement of said projection duringacceleration of said weight at points progressively further from saidinitial position of said projection as said control member rotates,whereby the point of interception of said cam with said line of movementfurthest from said rest position determines the degree of accelerationrequired to fully release said control member, and the time required tosweep said cam fully past said line of movement determines the minimumdelay of said control member.

4. In an acceleration responsive delayed action control device of thetype having a control member driven by a clock mechanism, anacceleration responsive sliding weight for releasing said clockmechanism, and a spring biasing said weight to a rest position, a hollowdriving shaft in said clock mechanism, a torsion wire supported withinsaid hollow shaft and connected at one end thereto, a pin on said weightadapted to slide therewith away from an initial position responsive toacceleration, and a cam on said torsion wire adapted to be engaged bysaid pin in the rest position of said weight to retain said main drivingshaft of said clock mechanism in a wound position, said cam consistingof an integral extension of the other end of said torsion wire bent intoa plane parallel to the direction of sliding movement of said weight,said extension being curved so as to intersect the line of movement ofsaid pin at points progressively further from said initial position ofsaid pin as said clock mechanism unwinds, whereby the point ofinterception of said cam with said line of movement furthest from saidinitial point determines the degree of acceleration reqiured to fullyrelease said clock mechanism, and the time required to sweep said camfully past said line of movement determines the minimum delay of saidcontrol member.

No references cited.

